Abstract: A method is described for cooling a hydrocarbon-rich fraction, in particular of natural gas, wherein the hydrocarbon-rich fraction (1) is cooled against at least one coolant circuit (10-15), the coolant has at least nitrogen, carbon dioxide, methane and/or C2+ hydrocarbons, the coolant is compressed by means of at least one turbocompressor (C1) having one or more gas-lubricated sliding-ring seals, and as primary seal gas, a substream of the coolant and/or an external gas or gas mixture having substantially nitrogen and/or methane is fed to the turbocompressor (C1), and as secondary seal gas, nitrogen is fed. According to the invention, at least one nitrogen-rich stream (21) is withdrawn at least at times from the coolant circuit (10-15).

Abstract: A plate heat exchanger (10), in particular a brazed aluminium plate heat exchanger, has a heat exchange portion (12), which comprises two or more first passages (14a), through which a first fluid may flow, and two or more second passages (14b), through which a second fluid may flow, in such a way that heat exchange takes place between the first fluid and the second fluid. To reduce thermal stress inside the heat exchange portion (12), the heat exchange portion (12) comprises at least one layer (30) through which no fluid flows, which is arranged between two passages (14a, 14b) through which fluid may flow.